Background
I am a male in my mid 20s. For about 10 years now I have been struggling with life and severe depression. I never had any friends, my family hates me and treats me pretty bad, my social skills are lacking and I suffer from Aspergers. In October '18 everything that I had left crumbled into pieces and I was completely lost. Fortunately, I was lucky enough to pick up a new job, move to a new place and virtually turned my life upside-down. I was able to completely start a new life from scratch though sometimes it still seems to be a dream. At work I met so many nice co-workers who I really enjoy spending my time with and I am finally able to be in a non-hostile environment where people treat me fair. This helped me A LOT to recover from my depression - I am definitely not "cured" in any way, it surely takes a lot of time to let the wounds heal and make the experiences I wasn't able to in the past, but the positive environment and the new people around me are helping me.
My Current Situation
Currently I work in IT consulting as a developer and I ended up on a project with another co-worker who is a male in his late 20s. We have been working together the past 4 months at the client's office. Over the course of the project we have gotten to know each other and ended up having a lot of fun, spending much time not only at work but in our free time as well. I definitely consider him to be a friend of mine and we've shared a lot of personal details.
Our Friendship
Both consciously and unconsciously I have attributed much of my mental recovery to our friendship and the amount of time we spend together. Together we are having lunch every day at work and occassionally we're going out for a drink in the evening or he invites me for some pizza and beer at his place where we just hang out. I've tried to tell him what the time spent together means to me but it's really difficult to explain what this means to me.
Yesterday we were chatting and he mentioned something about a guy he is currently dating. This is the first time he's mentioned dating someone, though he had previously mentioned that he is gay.
My Reaction
When he told me about the guy he is dating I felt disppointed and sad as if I had lost something. As if I'd been rejected although this isn't actually the case since it's not about getting into a relationship with him. I don't understand why I felt this way, because I am not gay. I don't love him and I think am not interested in a (romantic) relationship with him. It seems to me I am erroneously attributing my feelings to him which makes me somewhat susceptible.
My Goal
I feel like it would be best to talk openly with him about this issue, since I'd like to be honest with him no matter how awkward my situation might sound for him. Frankly, I think he will be considerate towards me and we'll still hang out with each other. I'd like to know how I can talk to him about my feelings without jeopardizing our friendship.